The pudendal nerve and/or other sacral nerves originating from the sacral plexus include sensory and somatic nerves that innervate the external genitalia of both sexes. Additionally, these nerves innervate and control the contractions of the external sphincter of the anus and external sphincter of the bladder. A sphincter is an anatomical structure comprised mainly of circular muscle, which maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning.
In humans, the pudendal nerve and/or other sacral nerves of particular concern are comprised of fibers exiting from the second, third, and fourth sacral vertebrae (i.e., S2-S4). During a pelvic floor surgery, for example, these nerves are at a significant risk of being stretched, pinched, torn, or otherwise injured. Any such damage may result in a temporary or permanent loss of nerve signal transmission, and may potentially cause urinary and/or fecal incontinence.